Copper-catalyzed Ritter-type reaction of unactivated alkenes with dichloramine-T

Abstract

It was shown that dichloramine-T (1) reacted with cyclohexene in acetonitrile to give N1-(2-chlorocyclohexyl) amidine 2a and N-(2-chlorocyclohexyl)acetamide (3) via the competitive addition of acetonitrile and N-chloro-N-tosylamino anion to cyclohexenechloronium ion. This reaction can be catalyzed by Cu(OAc)2 , primarily affording 2a. Furthermore, the resulting 2a can be cyclized to benzimidazol 14a in good yield by treating with KOH in dioxane. © 2010 Verlag Helvetica Chimica Acta AG.